1. Field of the Invention
The present invention relates to a novel catalyst system for the preparation of cellular foams characterized by carbodiimide and isocyanurate linkages. More particularly the invention relates to the use of a catalyst system comprising (a) an alkanolaminotriazine, (b) a hexahydrotriazine, and (c) phenol or a substituted phenol in the preparation of cellular foams characterized by carbodiimide and isocyanurate linkages.
2. Prior Art
The preparation of foams containing carbodiimide and isocyanurate linkages is well known in the art. The art teaches that foams containing both linkages can be prepared by condensing an organic polyisocyanate with a catalyst which promotes both carbodiimide and isocyanurate linkages or with a co-catalyst system, one catalyst promoting carbodiimide linkages and one catalyst promoting isocyanurate linkages. Representative of such teachings are the disclosures found in U.S. Pat. Nos. 3,645,923; 3,657,161; 3,717,596; 3,723,366; 3,746,709, and 3,806,475.